I have a deep freezer (ice chest) that is traditional for holding freezables in a small, rectangular shaped white, insulated, box that holds the temperature below freezing. I am considering adding an electronic temperature control (110volt fuse that shuts off power when the temperature is in programmed range). So the power needed will be controlled rather than the default setting built into the freezer. What would my savings be? (estimates are welcomed)

Doesn't the freezer have a thermostat control built in? As an FYI, the recommended temp for a freezer is 0 degrees F, (-18 degrees C) - see https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm093704.htm I suspect if the freezer doesn't have a thermostat that you can control it's probably designed to operate at that temp already. You can check it with a thermometer to be sure. If you build this control unit I would not advise setting it to maintain temps much above 0 degrees, or you will find that food won't keep as long as they do now.

As for savings: it's impossible to say without knowing the SEER of the unit. But for every degree above 0 degrees that you run it at you should save about 1 or 2 percent in electricity. But again, I don't recommend operating the freezer above 0 degrees.

None, this is what the freezer already does.